\(15^{th}\) BEEN Conference - LUISS, 23 January 2026
DEM, University of Trento
DEM, University of Trento
DEM, University of Trento
Do non-binding promises increase cooperation in a five-player centipede?
Mechanisms:
How likely is a player to send a pass promise?
How likely is a player to cooperate after receiving a promise?
Key idea
In sequential chains, policy leverage may lie in eliciting explicit commitments, not in richer communication.
Centipede cooperation
Promises and cooperation
| Treatment | Promise (available?) | Mandatory promise (Take/Pass) | Fee for sending message |
|---|---|---|---|
| Baseline (B) | ✗ | ✗ | ✗ |
| Cheap Talk (C) | ✓ | ✓ | ✗ |
| Voluntary (V) | ✓ | ✗ | ✗ |
| Fee (F) | ✓ | ✗ | ✓ |
- H1 (Promises): take-up of pass promises differs by regime.
- H1a: Pass promises same in V and C.
- H1b: Pass promises lower in F than V.
- H2 (Cooperation): any promise regime increases Pass vs Baseline.
- H3 (Credibility/response):
- H3a: Pass promise triggers more passing in V than C (silence makes it “less coerced”).
- H3b: Pass promise triggers more passing in F than V (fee increases credibility).
Takeaway
Aggregate cooperation is driven primarily by the prevalence of explicit commitments, not by large credibility shifts conditional on a promise.
matteo.ploner@unitn.it
Casal, Mittone, Ploner — Promises in Sequential Cooperation